Optimizing Outcomes After Out-of-Hospital Cardiac Arrest With Innovative Approaches to Public-Access Defibrillation: A Scientific Statement From the International Liaison Committee on Resuscitation.

Out-of-hospital cardiac arrest is a global public health issue experienced by ≈3.8 million people annually. Only 8% to 12% survive to hospital discharge. Early defibrillation of shockable rhythms is associated with improved survival, but ensuring timely access to defibrillators has been a significant challenge. To date, the development of public-access defibrillation programs, involving the deployment of automated external defibrillators into the public space, has been the main strategy to address this challenge. Public-access defibrillator programs have been associated with improved outcomes for out-of-hospital cardiac arrest; however, the devices are used in <3% of episodes of out-of-hospital cardiac arrest. This scientific statement was commissioned by the International Liaison Committee on Resuscitation with 3 objectives: (1) identify known barriers to public-access defibrillator use and early defibrillation, (2) discuss established and novel strategies to address those barriers, and (3) identify high-priority knowledge gaps for future research to address. The writing group undertook systematic searches of the literature to inform this statement. Innovative strategies were identified that relate to enhanced public outreach, behavior change approaches, optimization of static public-access defibrillator deployment and housing, evolved automated external defibrillator technology and functionality, improved integration of public-access defibrillation with existing emergency dispatch protocols, and exploration of novel automated external defibrillator delivery vectors. We provide evidence- and consensus-based policy suggestions to enhance public-access defibrillation and guidance for future research in this area.

Theorising survivorship after intensive care: A systematic review of patient and family experiences.

AIMS AND OBJECTIVE: This systematic literature review explores and maps what we know about survivorship to understand how survivorship can be theoretically defined. BACKGROUND: Survivorship of critical illness has been identified as a challenge for the 21st Century. Whilst the use of the term 'survivorship' is now common in critical care, it has been borrowed from the cancer literature where the discourse on what survivorship means in a cancer context is ongoing and remains largely descriptive. In the absence of a theoretical understanding, the term 'survivorship' is often used in critical illness in a generic way, limiting our understanding of what survivorship is. The current COVID-19 pandemic adds to an urgency of understanding what intensive care unit (ICU) survivorship might mean, given the emerging long-term consequences of this patient cohort. We set out to explore how survivorship after critical illness is being conceptualised and what the implications might be for clinical practice and research. DESIGN: Integrated systematic literature review. The review protocol was registered with PROSPERO International Prospective Register of Systematic Reviews. PRISMA guidelines were followed and a PRISMA checklist for reporting systematic reviews completed. RESULTS: The three main themes around which the reviewed studies were organised are: (a) healthcare system; (b) ICU survivors' families; and (c) ICU survivor's identity. These three themes feed into an overarching core theme of 'ICU Survivorship Experiences'. These themes map our current knowledge of what happens when a patient survives a critical illness and where we are in understanding ICU survivorship. CONCLUSION: We mapped in this systematic review the different pieces of the jigsaw that emerge following critical illness to understand and see the bigger picture of what happens after patients survive critical illness. It is evident that existing research has mapped these connections, but what we have not managed to do yet is defining what survivorship is theoretically. We offer a preliminary definition of survivorship as a process but are aware that this definition needs to be developed further with patients and families.

Lessons from a pilot for uncontrolled donation after circulatory death in the ED in the UK.

Worldwide there is a shortage of available organs for patients requiring transplants. However, some countries such as France, Italy and Spain have had greater success by allowing donations from patients with unexpected and unrecoverable circulatory arrest who arrive in the ED. Significant advances in the surgical approach to organ recovery from donation after circulatory death (DCD) led to the establishment of a pilot programme for uncontrolled DCD in the ED of the Royal Infirmary of Edinburgh. This paper describes the programme and discusses the lessons learnt.

How to implement live video recording in the clinical environment: A practical guide for clinical services.

BACKGROUND: The use of video in healthcare is becoming more common, particularly in simulation and educational settings. However, video recording live episodes of clinical care is far less routine. AIM: To provide a practical guide for clinical services to embed live video recording. MATERIALS AND METHODS: Using Kotter's 8-step process for leading change, we provide a 'how to' guide to navigate the challenges required to implement a continuous video-audit system based on our experience of video recording in our emergency department resuscitation rooms. RESULTS: The most significant hurdles in installing continuous video audit in a busy clinical area involve change management rather than equipment. Clinicians are faced with considerable ethical, legal and data protection challenges which are the primary barriers for services that pursue video recording of patient care. DISCUSSION: Existing accounts of video use rarely acknowledge the organisational and cultural dimensions that are key to the success of establishing a video system. This article outlines core implementation issues that need to be addressed if video is to become part of routine care delivery. CONCLUSION: By focussing on issues such as staff acceptability, departmental culture and organisational readiness, we provide a roadmap that can be pragmatically adapted by all clinical environments, locally and internationally, that seek to utilise video recording as an approach to improving clinical care.

Optimising clinical performance during resuscitation using video evaluation.

Video evaluation of resuscitation is becoming increasingly integrated into practice in a number of clinical settings. The purpose of this review article is to examine how video may enhance clinical care during resuscitation. As healthcare and available therapeutic interventions evolve, re-evaluation of accepted paradigms requires data to describe current practice and support change. Analysis of video recordings affords creation of a framework to evaluate individual and team performance and develop unique and tailored strategies to optimise care delivery. While video has been used in a number of non-clinical settings, there has been a recent increase of video systems in the prehospital and other clinical areas. This paper reviews the key opportunities in the emergency department-based resuscitation setting to enhance ergonomics, technical and non-technical skills-at both team and individual level-through video-assisted care performance analysis and feedback.

Dynamic nurse leadership in high-pressure situations.

Traditionally, healthcare professionals have been expected to acquire technical skills while minimal attention has been paid to the non-technical skills (NTS) they require to work in complex health environments, such as resuscitation rooms. This article explains the importance of NTS in improving patient outcomes and why a model of dynamic nurse leadership is useful in resuscitative care.

A specialist, second-tier response to out-of-hospital cardiac arrest: setting up TOPCAT2.

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) is the most common, immediately life-threatening, medical emergency faced by ambulance crews. Survival from OHCA is largely dependent on quality of prehospital resuscitation. Non-technical skills, including resuscitation team leadership, communication and clinical decision-making are important in providing high quality prehospital resuscitation. We describe a pilot study (TOPCAT2, TC2) to establish a second tier, expert paramedic response to OHCA in Edinburgh, Scotland. METHODS: Eight paramedics were selected to undergo advanced training in resuscitation and non-technical skills. Simulation and video feedback was used during training. The designated TC2 paramedic manned a regular ambulance service response car and attended emergency calls in the usual manner. Emergency medical dispatch centre dispatchers were instructed to call the TC2 paramedic directly on receipt of a possible OHCA call. Call and dispatch timings, quality of cardiopulmonary resuscitation and return-of-spontaneous circulation were all measured prospectively. RESULTS: Establishing a specialist, second-tier paramedic response was feasible. There was no overall impact on ambulance response times. From the first 40 activations, the TC2 paramedic was activated in a median of 3.2 min (IQR 1.6-5.8) and on-scene in a median of 10.8 min (8.0-17.9). Bimonthly team debrief, case review and training sessions were successfully established. OHCA attended by TC2 showed an additional trend towards improved outcome with a rate of return of spontaneous circulation of 22.5%, compared with a national average of 16%. CONCLUSIONS: Establishing a specialist, second-tier response to OHCA is feasible, without impacting on overall ambulance response times. Improving non-technical skills, including prehospital resuscitation team leadership, has the potential to save lives and further research on the impact of the TOPCAT2 pilot programme is warranted.

Developing and evaluating a brief, socially primed video intervention to enable bystander cardiopulmonary resuscitation: A randomised control trial.

BACKGROUND: Over 30,000 people experience out-of-hospital cardiac arrest in the United Kingdom annually, with only 7-8% of patients surviving. One of the most effective methods of improving survival outcomes is bystander intervention in the form of calling the emergency services and initiating chest compressions. Additionally, the public must feel empowered to act and use this knowledge in an emergency. This study aimed to evaluate an ultra-brief CPR familiarisation video that uses empowering social priming language to frame CPR as a norm in Scotland. METHODS: In a randomised control trial, participants (n = 86) were assigned to view an ultra-brief CPR video intervention or a traditional long-form CPR video intervention. Following completion of a pre-intervention questionnaire examining demographic variables and prior CPR knowledge, participants completed an emergency services-led resuscitation simulation in a portable simulation suite using a CPR manikin that measures resuscitation quality. Participants then completed questionnaires examining social identity and attitudes towards performing CPR. RESULTS: During the simulated resuscitation, the ultra-brief intervention group's cumulative time spent performing chest compressions was significantly higher than that observed in the long-form intervention group. The long-form intervention group's average compressions per minute rate was significantly higher than the ultra-brief intervention group, however both scores fell within a clinically acceptable range. No other differences were observed in CPR quality. Regarding the social identity measures, participants in the ultra-brief condition had greater feelings of expected emergency support from other Scottish people when compared to long-form intervention participants. There were no significant group differences in attitudes towards performing CPR. CONCLUSIONS: Socially primed, ultra-brief CPR interventions hold promise as a method of equipping the public with basic resuscitation skills and empowering the viewer to intervene in an emergency. These interventions may be an effective avenue for equipping at-risk groups with resuscitation skills and for supplementing traditional resuscitation training.

Assessing feasibility of proposed extracorporeal cardiopulmonary resuscitation programmes for out-of-hospital cardiac arrest in Scotland via geospatial modelling.

BACKGROUND: Extracorporeal cardiopulmonary resuscitation (ECPR) can improve survival for refractory out-of-hospital cardiac arrest (OHCA). We sought to assess the feasibility of a proposed ECPR programme in Scotland, considering both in-hospital and pre-hospital implementation scenarios. METHODS: We included treated OHCAs in Scotland aged 16-70 between August 2018 and March 2022. We defined those clinically eligible for ECPR as patients where the initial rhythm was ventricular fibrillation, ventricular tachycardia, or pulseless electrical activity, and where pre-hospital return of spontaneous circulation was not achieved. We computed the call-to-ECPR access time interval as the amount of time from emergency medical service (EMS) call reception to either arrival at an ECPR-ready hospital or arrival of a pre-hospital ECPR crew. We determined the number of patients that had access to ECPR within 45 min, and estimated the number of additional survivors as a result. RESULTS: A total of 6,639 OHCAs were included in the geospatial modelling, 1,406 of which were eligible for ECPR. Depending on the implementation scenario, 52.9-112.6 (13.8-29.4%) OHCAs per year had a call-to-ECPR access time within 45 min, with pre-hospital implementation scenarios having greater and earlier access to ECPR for OHCA patients. We further estimated that an ECPR programme in Scotland would yield 11.8-28.2 additional survivors per year, with the pre-hospital implementation scenarios yielding higher numbers. CONCLUSION: An ECPR programme for OHCA in Scotland could provide access to ECPR to a modest number of eligible OHCA patients, with pre-hospital ECPR implementation scenarios yielding higher access to ECPR and higher numbers of additional survivors.

Factors affecting public access defibrillator placement decisions in the United Kingdom: A survey study.

Aim: This study aimed to understand current community PAD placement strategies and identify factors which influence PAD placement decision-making in the United Kingdom (UK). Methods: Individuals, groups and organisations involved in PAD placement in the UK were invited to participate in an online survey collecting demographic information, facilitators and barriers to community PAD placement and information used to decide where a PAD is installed in their experiences. Survey responses were analysed through descriptive statistical analysis and thematic analysis. Results: There were 106 included responses. Distance from another PAD (66%) and availability of a power source (63%) were most frequently used when respondents are deciding where best to install a PAD and historical occurrence of cardiac arrest (29%) was used the least. Three main themes were identified influencing PAD placement: (i) the relationship between the community and PADs emphasising community engagement to create buy-in; (ii) practical barriers and facilitators to PAD placement including securing consent, powering the cabinet, accessibility, security, funding, and guardianship; and (iii) 'risk assessment' methods to estimate the need for PADs including areas of high footfall, population density and type, areas experiencing health inequalities, areas with delayed ambulance response and current PAD provision. Conclusion: Decision-makers want to install PADs in locations that maximise impact and benefit to the community, but this can be constrained by numerous social and infrastructural factors. The best location to install a PAD depends on local context; work is required to determine how to overcome barriers to optimal community PAD placement.

Association between sex and survival after out-of-hospital cardiac arrest: A systematic review and meta-analysis.

The current literature on sex differences in 30-day survival following out-of-hospital cardiac arrest (OHCA) is conflicting, with 3 recent systematic reviews reporting opposing results. To address these contradictions, this systematic literature review and meta-analysis aimed to synthesize the literature on sex differences in survival after OHCA by including only population-based studies and through separate meta-analyses of crude and adjusted effect estimates. MEDLINE and Embase databases were systematically searched from inception to March 23, 2022 to identify observational studies reporting sex-specific 30-day survival or survival until hospital discharge after OHCA. Two meta-analyses were conducted. The first included unadjusted effect estimates of the association between sex and survival (comparing males vs females), whereas the second included effect estimates adjusted for possible mediating and/or confounding variables. The PROSPERO registration number was CRD42021237887, and the search identified 6712 articles. After the screening, 164 potentially relevant articles were identified, of which 26 were included. The pooled estimate for crude effect estimates (odds ratio [OR], 1.42; 95% confidence interval [CI], 1.22-1.66) indicated that males have a higher chance of survival after OHCA than females. However, the pooled estimate for adjusted effect estimates shows no difference in survival after OHCA between males and females (OR, 0.93; 95% CI, 0.84-1.03). Both meta-analyses involved high statistical heterogeneity between studies: crude pooled estimate I2 = 95.7%, adjusted pooled estimate I2 = 91.3%. There does not appear to be a difference in survival between males and females when effect estimates are adjusted for possible confounding and/or mediating variables in non-selected populations.

Association of socioeconomic status with 30-day survival following out-of-hospital cardiac arrest in Scotland, 2011-2020.

BACKGROUND AND AIMS: The aim of this study was to investigate the crude and adjusted association of socioeconomic status with 30-day survival after out-of-hospital cardiac arrest (OHCA) in Scotland and to assess whether the effect of this association differs by sex or age. METHODS: This is a population-based, retrospective cohort study, including non-traumatic, non-Emergency Medical Services witnessed patients with OHCA where resuscitation was attempted by the Scottish Ambulance Service, between April 1, 2011 and March 1, 2020. Socioeconomic status was defined using the Scottish Index of Multiple Deprivation (SIMD). The primary outcome was 30-day survival after OHCA. Crude and adjusted associations of SIMD quintile with 30-day survival after OHCA were estimated using logistic regression. Effect modification by age and sex was assessed by stratification. RESULTS: Crude analysis showed lower odds of 30-day survival in the most deprived quintile relative to least deprived (OR 0.74, 95%CI 0.63-0.88). Adjustment for age, sex and urban/rural residency decreased the relative odds of survival further (OR 0.56, 95%CI 0.47-0.67). The strongest association was observed in males < 45 years old. Across quintiles of increasing deprivation, evidence of decreasing trends in the proportion of those presenting with shockable initial cardiac rhythm, those receiving bystander cardiopulmonary resuscitation and 30-day survival after OHCA were found. CONCLUSIONS: Socioeconomic status is associated with 30-day survival after OHCA in Scotland, favouring people living in the least deprived areas. This was not explained by confounding due to age, sex or urban/rural residency. The strongest association was observed in males < 45 years old.

Global variation in the incidence and outcome of emergency medical services witnessed out-of-hospital cardiac arrest: A systematic review and meta-analysis.

AIM OF THE REVIEW: To examine global variation in the incidence and outcomes of emergency medical services (EMS) witnessed out-of-hospital cardiac arrest (OHCA). DATA SOURCES: We systematically reviewed four electronic databases for studies between 1990 and 5th April 2021 reporting EMS-witnessed OHCA populations. Studies were included if they reported sufficient data to calculate the primary outcome of survival to hospital discharge or 30-day survival. Random-effects models were used to pool incidence and survival outcomes, and meta-regression was used to examine sources of heterogeneity. Study quality was appraised using the Joanna Briggs Institute critical appraisal tools. RESULTS: The search returned 1178 non-duplicate titles of which 66 articles comprising 133,981 EMS-witnessed patients treated by EMS across 33 countries were included. All but one study was observational and only 12 studies (18%) were deemed to be at low risk of bias. The pooled incidence of EMS-treated cases was 4.1 per 100,000 person-years (95% CI: 3.5, 4.7), varying almost 4-fold across continents. The pooled proportion of survivors to hospital discharge or 30-days was 20% overall (95% CI: 18%, 22%; I2 = 98%), 43% (95% CI: 37%, 49%; I2 = 94%) for initial shockable rhythms and 6% (95% CI: 5%, 8%; I2 = 79%) for initial non-shockable rhythms. In the meta-regression analysis, only region and aetiology were significantly associated with survival. When compared to studies from North America, pooled survival was significantly higher in studies from Europe (14% vs. 26%; p = 0.04) and Australasia (14% vs. 31%, p < 0.001). CONCLUSION: We identified significant global variation in the incidence and survival outcome of EMS-witnessed OHCA. Further research is needed to understand the factors contributing to these variations.

Identifying patients at risk of futile resuscitation: palliative care indicators in out-of-hospital cardiac arrest.

OBJECTIVES: Patients with indicators for palliative care, such as those with advanced life-limiting conditions, are at risk of futile cardiopulmonary resuscitation (CPR) if they suffer out-of-hospital cardiac arrest (OHCA). Patients at risk of futile CPR could benefit from anticipatory care planning (ACP); however, the proportion of OHCA patients with indicators for palliative care is unknown. This study quantifies the extent of palliative care indicators and risk of CPR futility in OHCA patients. METHODS: A retrospective medical record review was performed on all OHCA patients presenting to an emergency department (ED) in Edinburgh, Scotland in 2015. The risk of CPR futility was stratified using the Supportive and Palliative Care Indicators Tool. Patients with 0-2 indicators had a 'low risk' of futile CPR; 3-4 indicators had an 'intermediate risk'; 5+ indicators had a 'high risk'. RESULTS: Of the 283 OHCA patients, 12.4% (35) had a high risk of futile CPR, while 16.3% (46) had an intermediate risk and 71.4% (202) had a low risk. 84.0% (68) of intermediate-to-high risk patients were pronounced dead in the ED or ED step-down ward; only 2.5% (2) of these patients survived to discharge. CONCLUSIONS: Up to 30% of OHCA patients are being subjected to advanced resuscitation despite having at least three indicators for palliative care. More than 80% of patients with an intermediate-to-high risk of CPR futility are dying soon after conveyance to hospital, suggesting that ACP can benefit some OHCA patients. This study recommends optimising emergency treatment planning to help reduce inappropriate CPR attempts.

Incidence, characteristics and outcomes of out-of-hospital cardiac arrests in patients with psychiatric illness: A systematic review.

AIM: To conduct a systematic literature review of the existing evidence on incidence, characteristics and outcomes after out-of-hospital cardiac arrest (OHCA) in patients with psychiatric illness. METHODS: We searched Embase, Medline, PsycINFO and Web of Science using a comprehensive electronic search strategy to identify observational studies reporting on OHCA incidence, characteristics or outcomes by psychiatric illness status. One reviewer screened all titles and abstracts, and a second reviewer screened a random 10%. Two reviewers independently performed data extraction and quality assessment. RESULTS: Our search retrieved 11,380 studies, 10 of which met our inclusion criteria (8 retrospective cohort studies and two nested case-control studies). Three studies focused on depression, whilst seven included various psychiatric conditions. Among patients with an OHCA, those with psychiatric illness (compared to those without) were more likely to have: an arrest in a private location; an unwitnessed arrest; more comorbidities; less bystander cardiopulmonary resuscitation; and an initial non-shockable rhythm. Two studies reported on OHCA incidence proportion and two reported on survival, showing higher risk, but lower survival, in patients with psychiatric illness. CONCLUSION: Psychiatric illness in relation to OHCA incidence and outcomes has rarely been studied and only a handful of studies have reported on OHCA characteristics, highlighting the need for further research in this area. The scant existing literature suggests that psychiatric illness may be associated with higher risks of OHCA, unfavourable characteristics and poorer survival. Future studies should further investigate these links and the role of potential contributory factors such as socioeconomic status and comorbidities.

Increasing lay-people's intentions to initiate CPR in out of hospital cardiac arrest: Results of a mixed-methods 'before and after' pilot study of a behavioural text-message intervention (BICeP).

Background: Prompt, effective cardio-pulmonary resuscitation (CPR) increases survival in out-of-hospital cardiac arrest. However, CPR is often not provided, even by people with training. Low confidence, perceptions of risks and high emotion can prevent initiation of CPR. Behaviour-change techniques may be helpful in increasing CPR rates. Aim: To pilot a text-message behavioural intervention designed to increase intentions to initiate CPR, explore participant responses and pilot methods for future randomised controlled trial of effectiveness. Methods: A 'before and after' pilot study plus qualitative interviews was undertaken. Participants were lay-people who had undertaken CPR training in previous 2 years.Participants were sent an intervention, comprising 35 text-messages containing 14 behaviour-change techniques, to their mobile phone over 4-6 weeks.Primary outcome: intentions to initiate CPR assessed in response to 4 different scenarios.Secondary outcomes: theory-based determinants of intention (attitudes, subjective norms, perceived behavioural control and self-efficacy) and self-rated competence. Results: 20 participants (6 female, 14 male), aged 20-84 provided baseline data. 17 received the full suite of 35 text messages.15 provided follow-up data. Intentions to perform CPR in scenarios where CPR was indicated were high at baseline and increased (18.1 ± 3.2-19.5 ± 1.8/21) after the intervention, as did self-efficacy and self-rated competency. Self-efficacy, attitudes, perceived behavioural control and subjective norms were positively correlated with intentions. Qualitative data suggest the intervention was perceived as useful. Additional options for delivery format and pace were suggested. Conclusions: Pilot-testing suggests a text-message intervention delivered after CPR training is acceptable and may be helpful in increasing/maintaining intentions to perform CPR.

Optimizing outcomes after out-of-hospital cardiac arrest with innovative approaches to public-access defibrillation: A scientific statement from the International Liaison Committee on Resuscitation.

Out-of-hospital cardiac arrest is a global public health issue experienced by ≈3.8 million people annually. Only 8% to 12% survive to hospital discharge. Early defibrillation of shockable rhythms is associated with improved survival, but ensuring timely access to defibrillators has been a significant challenge. To date, the development of public-access defibrillation programs, involving the deployment of automated external defibrillators into the public space, has been the main strategy to address this challenge. Public-access defibrillator programs have been associated with improved outcomes for out-of-hospital cardiac arrest; however, the devices are used in <3% of episodes of out-of-hospital cardiac arrest. This scientific statement was commissioned by the International Liaison Committee on Resuscitation with 3 objectives: (1) identify known barriers to public-access defibrillator use and early defibrillation, (2) discuss established and novel strategies to address those barriers, and (3) identify high-priority knowledge gaps for future research to address. The writing group undertook systematic searches of the literature to inform this statement. Innovative strategies were identified that relate to enhanced public outreach, behavior change approaches, optimization of static public-access defibrillator deployment and housing, evolved automated external defibrillator technology and functionality, improved integration of public-access defibrillation with existing emergency dispatch protocols, and exploration of novel automated external defibrillator delivery vectors. We provide evidence- and consensus-based policy suggestions to enhance public-access defibrillation and guidance for future research in this area.

Socioeconomically equitable public defibrillator placement using mathematical optimization.

BACKGROUND: Mathematical optimization can be used to place automated external defibrillators (AEDs) in locations that maximize coverage of out-of-hospital cardiac arrests (OHCAs). We sought to determine whether optimization can improve alignment between AED locations and OHCA counts across levels of socioeconomic deprivation. METHODS: All suspected OHCAs and registered AEDs in Scotland between Jan. 2011 and Sept. 2017 were included and mapped to a corresponding socioeconomic deprivation level using the Scottish Index of Multiple Deprivation (SIMD). We used mathematical optimization to determine optimal locations for placing 10%, 25%, 50%, and 100% additional AEDs, as well as locations for relocating existing AEDs. For each AED placement policy, we examined the impact on AED distribution and OHCA "coverage" (suspected OHCA occurring within 100 m of AED) with respect to SIMD quintiles. RESULTS: We identified 49,432 suspected OHCAs and 1532 AEDs. The distribution of existing AED locations across SIMD quintiles significantly differed from the distribution of suspected OHCAs (P < 0.001). Optimization-guided AED placement increased coverage of suspected OHCAs compared to existing AED locations (all P < 0.001). Optimization resulted in more AED placements and increased OHCA coverage in areas of greater socioeconomic deprivation, such that resulting distributions across SIMD quintiles matched the shape of the OHCA count distribution. Optimally relocating existing AEDs achieved similar OHCA coverage levels to that of doubling the number of total AEDs. CONCLUSIONS: Mathematical optimization results in AED locations and suspected OHCA coverage that more closely resembles the suspected OHCA distribution and results in more equitable coverage across levels of socioeconomic deprivation.

Issues around conducting prehospital research on out-of-hospital cardiac arrest: lessons from the TOPCAT study.

Outcome from OHCA is primarily determined by prehospital events and meaningful clinical OHCA research must include data recorded in this setting. There is little evidence on which to base the practice of prehospital resuscitation and research in this area presents huge challenges but is required if survival from OHCA is to improve. This short report aims to provide a practical guide to performing prehospital research on OHCA, based on lessons learned from the Temperature Post Cardiac Arrest (TOPCAT) research; an observational study into OHCA.